Self-centering washer



June 15, 1937. J NAPIER 2,083,658

SELF CENTERING WASHER Filed March 30, 1935 77mm JAMES ALEXANDER THGMSQN NAPIER, 27 \J 4 a Patented June 15, 1937 UNITED STATES SELF-CENTERING WASHER James Alexander Thomson Napier, London, England, assignor of two-thirds to Edwin James Hall and Hugh John Hall, London, England Application March 30, 1935, Serial No. 13,826 In Great Britain April 4, 1934 7 Claims. (01. sass-#1) This invention relates to self-centering washers or the like which are applicable for various purposes, and has for its object to provide an improved device of this kind.

Various disadvantages have been met with in connection with washers failing to accurately center themselves in an operative position surrounding a stud or the like projection which the washer is required to pack relatively to another part such as a nut adapted to be screwed tightly down upon the base of the stud or the like, the disadvantages of such inaccurate centering of the washer taking different forms in different kinds of apparatus. As an important instance the following may be mentioned. a

In connection with the adjustment of the fuse of artillery projectiles of the kind having the usual ogival-shaped heads, whether acting upon impact by the explosion of a charge of a high explosive or by time as in the case of shrapnel shells a washer is passed over the nose-stud of the projectile and is inserted between the base of the said stud and the fuse. Owing to the undercut annular groove (which is necessary for manufacturing purposes) surrounding the base of the externally screwed nose-stud it is possible for the washer to assume a slightly eccentric position relatively to the adjusted fuse and the nosestud of the projectile and the slight lateral projection of the washer due to said eccentricity produces drift of the projectile when fired from a gun and consequently inaccurate shooting. The greater the range or the distance of the target aimed at from the gun the greater is the said drift and the more inaccurate the shooting. Great efforts have been made to minimize this disadvantage by instructing and training the gun-teams to accurately center the washer in its operative position upon the nose of the projectile before the latter is inserted in the gun but owing to the usual hurry and heat of serving artillery guns it is desirable to remove this cause of inaccurate shooting as much as possible independently of the training of the personnel serving the guns and this object is achieved by means of the self-centering washer according to my present invention which accurately centers itself relatively to the nose-stud of the projectile merely by the act of screwing the fuse tightly into position upon the said nose-stud.

The improved washer according to the invention comprises a main ring portion and an easily deformable portion or portions formed in one therewith or secured thereto and is characterized in that such deformable portion or portions is or are inwardly and axially directed and the inner edge or edges thereof is or are disposed on the circumference of a circle concentric with said main ring portion, said deformable portion or portions being adapted when deformed to close 5 onto the stem or undercut of the stud or the like, thereby automatically centralizing said washer. The said deformable portion or portions is or are disposed at an angle to a plane normal to the axis of the washer and may be directed away 10 from the main body portion thereof and flexibility may be increased by provision of a plurality of cuts or recesses in the perimeter.

Referring to the drawing filed herewith:

Figure 1 is a plan of one form of washer made 15 in accordance with this invention and designed for use on the nose-stud of an artillery projectile.

Figure 2 is a section on the line 2-2 of Figure 1 to an enlarged scale.

Figure 3 is a part sectional elevation of a projectile showing the washer in position after screwing down the fuse.

Figure 4 is a view to an enlarged scale of the projectile shown in Figure 3 before the fuse has been screwed onto the cap. 25

Figure 5 is a similar View to Figure 3 to an enlarged scale.

In the form shown in the drawing the washer is made of copper and asbestos and comprises a rigid main portion a in the form of a copper an- 30 nulus of U section which embraces an annulus of asbestos b. The lower surface of the main portion a is shaped to correspond with the annular seating on the nose cap of the projectile on which the washer is to be used. Formed in one 35 with the upper edge portion a and extending inwardly and upwardly is a flexible portion 0 provided with a number of notches d to increase the flexibility. The flexible portion 0 is curved so that the degree of axial direction increases towards the inner edge. At the base of the screw thread on the fuse f is an undercut g. The washer is carefully passed over the threads of the fuse until the flexible portion 0 rests on the sealing g. The fuse is then screwed into the nose cap, 45 the flnal tightening thereof forcing the flexible portion into the undercut g, thereby effectively centralizing the washer between the fuse and the nose cap. If the washer is placed on the fuse in an inverted position the perimeter of the flex- 5 ible portion will be engaged by the face having the start of the internal thread on the fuse and as the thread has a helical surface, the flexible portion in contact with the helical surface will be deformed unequally resulting in eccentrically poconnection with various kinds of apparatus other than with artillery ammunition, particularly in cases where the accurate centering of the washer is required in order to prevent the leakage of f a fluid under pressure, for example, in connection with aircraft, certain kinds of internal combustion engines and other machines in which highly compressed fluids whether air or gases are employed.

What I claim and desire to Patent is:

1. For use with a plurality of members of rigid material adapted to be screwed together in a fluid-tight manner, one of said members having a seat, and another of saidmembers having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a main ring portion, an inwardly directed portion, and an easily deformable portion operatively associated with said main ring portion, said easily deformable portion being of softer secure by Letters material than said members and inwardly and axially directed, the inner edge thereof being disposed on the circumference of a circle concentric with said main ring portion, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved toward seat seat.

2. For use with a plurality of members of rigid material adapted to be screwed together in a fluid-tight manner, one of said members having a seat and another of said members having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a main ring portion, an inwardly directed portion, and an easily deformable portion operatively associated with said main ring portion, said easily deformable portion being of softer material than said members and inwardly and axially directed, the inner edge thereof being disposed on the circumference of a circle concentric with said main ring portion, said easily deformable portion comprising a plurality of segments disposed in spaced relation separated by notches, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved towards said seat.

3. For use with a pluralityof members of rigid material adapted to be screwed together in a. fluid-tight manner, one of said members having a seat and another of said members having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a main ring portion, an inwardly directed portion, and an easily deformable portion operatively associated with said main ring portion, said easily deformable portion being of softer material than said member and inwardly and axially directed and curved so that the degree of axial direction increases towards the inner edge, the said inner edge thereof being disposed on the circumference I of a circle concentric with said main ring portion, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved toward said seat.

4. For use with a plurality of members of rigid material adapted to be screwed together in a fluid-tight manner, one of said members having a seat and another of said members having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a ring member of generally U-shaped cross section with the legs directed inwardly, one of said legs being easily deformable, said easily deformable leg being of softer material thansaid members and axially directed, and curved so that the degree of axial direction increases towards the inner edges, the said inner edge thereof being disposed on the circumference of a circle concentric with said ring member, said easily deformable leg comprising a plurality of segments disposed in spaced relation separated by notches, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved towards said seat.

5. For use with a plurality of members of rigid material adapted to be screwed together in a fluid-tight manner, one of said members having a seat, and another of said members having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a main ring portion, an inwardly directed portion, and an easily deformable portion operatively associated With said main ring portion, said easily deformable portion being of softer material than said members and inwardly and axially directed and disposed at an angle to a plane normal to the axis of the sealing washer, and directed away from the main body portion thereof, the inner edge of the deformable portion being disposed on the circumference of a circle concentric with said main ring portion, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved toward said seat.

6. For use with a plurality of members of rigid material adapted to be screwed together in a fluid-tight manner, one of said members having a seat, and another of said members having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a ring member of general U-shape cross section with the legs directed inwardly, one of said legs easily deformable, said easily deformable leg being of softer material than said members and axially directed and disposed at an angle to a plane normal to the axis of the sealing washer, and directed away from the main body portion thereof, the inner edge of the deformable leg being disposed on the circumference of a circle concentric with said ring member, said easily deformable leg comprising a plurality of segments, disposed in spaced relation and separated by notches, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved toward said seat.

7. For use with a plurality of members of rigid material adapted to be screwed together in a fluid-tight manner, one of said members having a seat, and another of said members having a head, a screw threaded cylindrical portion cut away adjacent said head to form an undercut and adapted to be screwed into said seat provided member; a sealing washer adapted to be slid over said screw threaded portion comprising a ring member formed as a U-section annulus containing asbestos or other packing, an inwardly directed portion, and an easily deformable portion formed as an extension to one arm of said U-portion, said easily deformable portion being of softer material than said members and axially directed, the inner edge of the deformable portion thereof being disposed on the circumference of a circle concentric with said ring member, said inner edge being adapted to contact with said head and be thereby pressed into said undercut to automatically center said sealing washer with respect to said members when said head is moved toward said seat.

JAMES ALEXANDER THOMSON NAPIER. 

